000
FXUS63 KDLH 060330
AFDDLH
Area Forecast Discussion
National Weather Service Duluth MN
930 PM CST Mon Dec 5 2016
.UPDATE...
Issued at 930 PM CST Mon Dec 5 2016
Last band of moderate to heavy snow was located along the
international border area at 03Z/9pm. This band will continue into
Canada. Elsewhere, some light snow along the eastern Iron Range
into the Arrowhead. Very little snow noted downstream. Latest
HRRR/DLH WRF no longer support the previous forecast winter
weather advisories and have dropped, except over the Arrowhead. 3
to 5 inches is still possible, especially in the higher terrain.
UPDATE Issued at 624 PM CST Mon Dec 5 2016
A band of moderate to heavy snow was lifting northeastward through
northeast Minnesota this evening. Some snow reports of 1 to 2
inches in roughly 1.5 to 2 hours have been received. Expect this
band to continue to move through the rest of northeast Minnesota
this evening. A break in the action elsewhere as a dry slot is
punching into the forecast area from the southwest. This may play
in role in the advisory. Will continue to monitor, but with very
little precipitation downstream per mosaic of Upper Midwest
radars, may have to make some adjustments.
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 252 PM CST Mon Dec 5 2016
A developing low pressure system will lead to a period of rain and
snow across the Northland this evening into tonight, with heavy snowlikely for parts of northern Minnesota.
On the synoptic scale a mid-level shortwavetrough is currently
ejecting out of the Rockies into the central Plains, with a
resulting surface low starting to develop along the North
Dakota/Minnesota border per 3-hour pressure fall analysis. With the
low to the west, a warm front will lift north across northern
Minnesota and northwest Wisconsin tonight with seasonably strong
warm air advection aloft. This warm air advection combined with the
mid-level PVA from the shortwavetrough will result in precipitation
rapidly developing and expanding across the Northland this evening,
with radar returns and surface observing stations already reporting
rain/snow falling in east-central Minnesota at of 3pm. Temperatures
at the surface are near-freezing, and until the colder air aloft
wraps around the low late tonight surface temps will likely be
steady if not rising slightly behind the warm front. Since temps
shouldn`t be too much above freezing, the precipitation rate should
overcome any melting causing by warm air near the surface thus
precipitation should be mainly snow. However, where large-scale
forcing will be weaker, such as in northwest Wisconsin, precip will
probably fall as more of a rain/snow mix resulting in limited
accumulation.
As the low lifts north a well-modeled dry slot will likely work its
way in after midnight towards Tuesday morning. This could result in
areas of light freezing drizzle within the dry slot due to the loss
of ice aloft, but given the true origin of the cold air that will
begin to wrap around the low tonight is from southern Saskatachewan,
think there will be enough ice in the column to result in more
flurries than freezing drizzle. The low will lift north towards Lake
of the Woods Tuesday with colder air continuing to wrap around it,
causing light snow showers off and on through the day. Along the
north shore strong southeasterly winds will likely lend to a bit of
lake enhancement late tonight into Tuesday, so the highest snowfall
amounts for this storm will likely be along the higher terrain of
the north shore.
With this rapidly deepening low so close, winds will increase
tonight into tomorrow. Southeast winds will be breezy this evening,
becoming south to southwesterly on Tuesday. Winds will be 10-15mph
overnight, increasing to 15-20mph on Tuesday afternoon with gusts
over 30 mph. Tonight, these winds will aid in keeping areas along
the Lake Superior shoreline above freezing and thus resulting in
lower snowfall amounts as rain mixes with snow. However, late
tonight into Tuesday these stronger winds will result in a some
blowing and drifting snow, especially in north central Minnesota
such as Walker and the Brainerd Lakes region.
Total snowfall amounts around 3 to 5 inches across northern
Minnesota tonight, mainly along and north of Highway 2 in northern
Minnesota. South of Highway 2 - Cass, Crow Wing, Aitkin, and Pine
counties in MN and much of northwest Wisconsin - lesser snowfall
amounts are expected, 1-3". In the Twin Ports and along the north
shore there will be a sharp gradient in snowfall between communities
right along the shoreline such as Two Harbors (1-2" at most) and up
in the higher terrain such as near Finland (4-6"+). In Duluth a
sharp gradient will be observed, with 1-2" downtown and 3-6" up
"above the hill" such as at our office near the airport.
.LONG TERM...(Tuesday night through Monday)
Issued at 251 PM CST Mon Dec 5 2016
Focus for long term lake effect snow is first significant fall
system Friday into the weekend wed night to thu night along with the
first cold blast of the season
The surface low will be along the the Canadian border with the gfs
locating it near the Lake of the Woods and the ecmwf locating the
center just south of INL tuesday night. Both models move the low
center into the northern great lakes by wednesday morning. The
northerly flow will continue to pull in the colder air and moisture
into the forecast region. This will keep snow showers across most
of the area. As indicated by the mid shift, formation of a gravity
along the northshore of Lake Superior is still possible so will keep
the current fcst in that area for Wednesday and Wednesday night.
With the northerly flow and much colder air (850T < -10C) and lake
temps around 4C-6C, snow showers will develop along the snowbelt
areas of northwest Wisconsin. The snow showers will be heavy at
times Thursday as the best conditions will affect the region.
Less favorable wind conditions along with decreasing moisture will
decrease the snow showers Thursday night before ending Friday
morning. Another short wave will move through the forecast region
Friday night and Saturday bringing a possibility of snow showers.
Another Low pressure system will move through the region late
Saturday night and Sunday bringing another round of light snow.
Temperatures will remain below normal through the period with below
zero readings possible over the weekend across the northern areas.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 624 PM CST Mon Dec 5 2016
MVFR and LIFR ceilings are found near the band of precipitation
moving through the terminals. After the precipitation passes,
ceilings return to VFR. With more VFR ceilings downstream in
southern Minnesota, this may eventually reach area terminals.
Gusty winds will be commonplace by midnight. Next round of snow is
on track for after 12Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 26 27 16 20 / 70 50 30 30
INL 27 29 18 24 / 90 70 50 50
BRD 24 24 15 18 / 40 60 20 20
HYR 28 29 17 21 / 80 70 30 20
ASX 30 33 21 24 / 60 40 30 30
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...Winter Weather Advisory until noon CST Tuesday for MNZ012-020-
021.
LS...Small Craft Advisory from 6 AM to 3 PM CST Tuesday for LSZ121-
143>148.
GaleWarning from 3 PM Tuesday to 9 AM CST Wednesday for LSZ121-
140>148.
Small Craft Advisory until 3 PM CST Tuesday for LSZ140>142.
&&
$$
UPDATE...GSF
SHORT TERM...JJM
LONG TERM...Stewart
AVIATION...GSF